The study population comprises 20 completely edentulous patients aged 60 years and older with severe mandible resorption. Each patient receives two inter-foraminal implants (Neoss Ltd., Harrogate, UK). Following randomization, implants are loaded either immediately after dental implant surgery or three months after implant placement with the Locator®-abutment system. At follow-up visits 3, 6 12, 24 and 36 months after loading, implant stability is evaluated with Periotest® and Ostell®.
Hypothesis: Especially for gerontoprosthetics, the Locator® abutment system offers the possibility of a minimally invasive retention of prosthetic total restorations of edentulous mandibles. The reduced number of 2 interforaminal implants is intended to ensure implantological anchoring with minimal surgical, technical, financial and time expenditure. Research Question: How safe is this minimally invasive and cost-effective implant and anchoring system in terms of long-term outcome? Are the two implant-prosthetic procedures (immediate versus late restoration) different in terms of implant survival time? Materials and methods Enrollment: * 20 patients without relevant pre-existing conditions, from the age of 60 years * edentulous mandible, alveolar ridge atrophy Statistical Analysis: When planning the study, it is estimated that bone resorption in the peri-implant area of the immediate-care implants is greater than in the late-treated implants. 10 patients per group are required with a t-test (α = 0.05) and a power of 80% if the null hypothesis is formulated as follows: -difference of means is 0 and the alternative - expected difference of means is 1mm, common standard deviation is 0.75. Collective A (open healing - immediate loading): Insertion of a new, prefabricated total mandibular prosthesis on the day of the operation immediately postoperatively after screwing in the Locator® abutments. Polymerization of the corresponding Locator® matrices in the newly incorporated lower jaw denture in the patient's mouth. Collective B (closed implant healing - conventional loading): 3 months after implantation Exposure of the primary closed implants. Immediately following insertion of the prefabricated full-thickness UK prosthesis and retention by the implants using Locator® abutments. Test parameters: 1. Intraoperative torque measurement in Ncm 2. Radiological measurement of periimplant bone height using orthopantomogram 3. 4-point measurement of peri-implant probing depth using WHO periodontal probe. The measurement is mesial, distal, buccal and lingual of the implant. 4. Measurement of bleeding on probing (parameters of peri-implant inflammation) using the WHO periodontal probe. 5. Analysis of implant stability using the Periotest® and Osstell® measuring instruments according to a standardized scheme: The strength values are performed in a measuring range consisting of a straight line through the center of the implant and the resulting 180 ° circle sector anterior to this line results. After multiple measurements (5-fold) the lowest numerical value for the Periotest® and for the RFA (Osstell®) the lowest value documented.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
19
interforaminal placement of 2 implants
immediate loading with a locator retained mandibular overdenture
conventional loading with a locator retained mandibular overdenture 3 months postoperatively
Medical University of Graz
Graz, Styria, Austria
Change of Implant stability
Evaluation of Implant stability with Resonance frequency analysis (Ostell®) indicating quality of osseointegration
Time frame: 0,3,6,12,24,36 months
Change of Implant stability
Evaluation of implant stability with electromechanical tapping (Periotest®) indicating quality of osseointegration
Time frame: 0,3,6,12,24,36 months
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